M65 is a great speaker.
I'm looking at getting 2 more when I move some of the others I have sitting around.
I think you need 2 of them minimum though. I like them on top in a 4x12. Not sure how just the 1 will sound.
The f70 is a wider less spiked vintage 30 with more low mids and strong response. I have 2 of thr regular f70 for many years I've kept them around. Great speakers. I bet it would sound really good with the m65 being I like the larger dustcap version f70 (h75) with it.. It also sounds good with a Redback... and a UK vintage 30....
I'm still curious to try the av60. Long as it doesn't fart out in the low end when pushed, it sounds like a great speaker. I always anticipate speaker use being a 4x12 with minimum of 2 speakers of the same being ran.
For example, I love greenbacks. But the way I dial the chunk into an amp and drive it, they can break up a little unpleasantly especially through girthy amps... I can't imagine just using one or 2 of them. Redbacks, different story, they love volume and 2 of them would be no problem for the way I like my tone dialed. But I figure 2 av30 probably sound pretty sweet.
The only thing that creates reserve for me with their av 75 version is an ear fatiguing high frequency response under gain.